server_status_health.js enables Mongos healthMonitoring with "test","ldap","dns" turned off. Then, it enables "test" facet with critical intensity and sets a failPoint to cause failure for it.

Then, it tests that the serverStatus call returns the essential parameters to show transient failure state. See attached screenshot. It also checks the duration on fault object and linked fault facet objects. They are checked for equality which can fail in certain delayed scenarios. 

assert.eq(kTestObserverFacet.duration, faultInformation.duration);

Suggestion: Remove the check or have the fault facet check duration less than equal to fault duration check. 

fault.cpp
void Fault::appendDescription(BSONObjBuilder* builder) const {   
 builder->append("id", getId().toBSON());  
 builder->append("duration", getDuration().toBSON());    
BSONObjBuilder facetsBuilder;    
for (auto& facet : _facets) {           facetsBuilder.append(FaultFacetType_serializer(facet->getType()), facet->toBSON());  
}
builder->append("facets", facetsBuilder.obj());    
builder->append("numFacets", static_cast<int>(_facets.size()));
}